Continuous nerve block assembly

Abstract

An assembly and method for continuous blockage of a nerve in a patient. The assembly includes a needle comprising a hollow needle conduit having a shaft portion and a tip portion, a generally non-conductive layer disposed along a length of the conduit shaft portion, and an echogenic surface extending along at least a portion of the needle. A catheter having a bore for transmittal of an anesthetic to the nerve is receivable in the shaft portion of said needle. Following insertion of the needle tip in the vicinity of the nerve by electrical nerve stimulation and ultrasound visualization, the catheter is passed through the needle conduit such that the distal end of the catheter extends beyond the distal tip of the needle. The catheter has an echogenic portion, such as a ribbon wrapped around the distal end of the catheter, and the catheter echogenic portion is guidable in the vicinity of the nerve under ultrasound imaging. Following placement of the catheter, the needle may be removed, leaving the catheter in position for delivering continuous, spaced doses of the anesthetic over a selected period of time.

1 . An assembly for providing continuous blocking of a nerve of a patient, comprising: 
 a needle comprising a hollow needle conduit having a shaft portion and a tip portion, a generally non-conductive layer disposed along a length of said conduit shaft portion, and an echogenic surface extending along at least a portion of said needle; and    a catheter comprising a catheter shaft having a proximal end and a distal end, said catheter sized to be received in said shaft portion of said needle, said catheter shaft having a bore for transmittal of an anesthetic to a vicinity of said nerve.    
   
   
       2 . The assembly of  claim 1 , wherein at least a portion of said catheter is provided with an echogenic capability such that said catheter portion is visible under ultrasound visualization  
   
   
       3 . The assembly of  claim 2 , wherein said echogenic capability comprises an echogenic surface disposed along at least a portion of a length of said catheter shaft.  
   
   
       4 . The assembly of  claim 3 , wherein said needle is capable of providing electrical stimulation to said nerve, and said respective needle and catheter echogenic surfaces are arranged for enhancing a reflection of ultrasound waves generated during said ultrasound visualization.  
   
   
       5 . The assembly of  claim 4 , wherein said catheter echogenic surface is disposed along the distal end of said catheter shaft.  
   
   
       6 . The assembly of  claim 4 , wherein said catheter echogenic surface comprises a band fitted over a portion of said catheter shaft, said band comprising an outer surface having deformations formed thereon for enhancing said reflection of ultrasound waves.  
   
   
       7 . The assembly of  claim 4 , wherein said catheter echogenic surface comprises a coiled ribbon wrapped along at least a distal portion of said catheter, at least a portion of said coiled ribbon having deformations formed thereon for enhancing said reflection of ultrasound waves.  
   
   
       8 . The assembly of  claim 7 , wherein said distal portion of said catheter has a flexibility, and said coiled ribbon is wrapped along said distal portion in a manner such that said flexibility is substantially maintained.  
   
   
       9 . The assembly of  claim 4 , wherein said respective echogenic surfaces are arranged such that a reflection of ultrasound waves from said needle echogenic surface generated during ultrasound visualization is visually distinct from a reflection of ultrasound waves from said catheter echogenic surface.  
   
   
       10 . The assembly of  claim 4 , wherein said needle echogenic surface comprises an outer layer covering at least a portion of said generally non-conductive layer, said outer layer comprising a plurality of deformations disposed along a length thereof, said hollow needle conduit being structured such that said conduit is electrically conductive upon electrical connection to a conducting electrode, and wherein said generally non-conductive layer substantially covers said conduit shaft portion and not said tip portion.  
   
   
       11 . A method for continuous blockage of a nerve of a patient, comprising: 
 providing a hyperechoic stimulating block needle, said needle comprising an electrically conductive hollow needle conduit, said conduit having a shaft portion and a distal tip, a generally non-conductive layer extending along said conduit shaft portion, and an echogenic surface extending along at least a portion of a length of said needle;    inserting said needle tip into a patient in a vicinity of said nerve, and aligning said needle tip in proximity with said nerve by visualization with ultrasonic imaging and by electrical nerve stimulation;    passing a catheter through said hollow needle conduit such that a distal end of said catheter extends distally beyond said needle tip, said catheter distal end having an echogenic surface along a length thereof;    aligning a distal end of said catheter in proximity with said nerve by ultrasonic imaging; and    injecting an anesthetic suitable for blocking said nerve into said patient through said catheter.    
   
   
       12 . The method of  claim 11 , wherein said inserting step comprises inserting said needle tip into a neurovascular sheath surrounding said nerve, and injecting an amount of anesthetic through said needle to create a local expansion of said neurovascular sheath; and wherein said catheter is passed through said hollow needle conduit such that the distal end of said catheter extends into said neurovascular sheath, and wherein the needle is withdrawn following introduction of said catheter into said neurovascular sheath.  
   
   
       13 . The method of  claim 11 , wherein said injecting step comprises injecting multiple, spaced doses of said anesthetic over a selected time period.  
   
   
       14 . The method of  claim 11 , wherein said electrical nerve stimulation comprises emitting an electrical pulse in a vicinity of said nerve, and adjusting an amount of current to elicit a motor response when said needle tip is advanced toward said nerve.  
   
   
       15 . The method of  claim 11 , wherein said echogenic surface of said catheter comprises a band positioned along a length of said catheter, said band comprising deformations shaped and positioned along a surface of said band to enhance ultrasonic wave deflection.  
   
   
       16 . The method of  claim 11 , wherein said catheter comprises a generally flexible polymeric composition, and wherein said echogenic surface of said catheter comprises a ribbon positioned around a surface of said catheter in a manner such that the flexibility of said catheter is substantially maintained, said ribbon comprising deformations shaped and positioned along a surface of said ribbon to enhance ultrasonic wave deflection.  
   
   
       17 . The method of  claim 11 , wherein said respective needle and catheter echogenic surfaces are structured and arranged such that a reflection of ultrasound waves from said needle echogenic surface generated during ultrasound visualization is visually distinct from a reflection of ultrasound waves from said catheter echogenic surface.  
   
   
       18 . An echogenic catheter suitable for ultrasonic visualization during a medical procedure, comprising: 
 a catheter shaft having a proximal end, a distal end, and a bore extending at least partially therethrough, said catheter shaft formed from a generally flexible polymeric composition;    a coiled ribbon wrapped around at least a distal portion of said catheter shaft, said coiled ribbon comprising deformations shaped and positioned along a surface of said ribbon to reflect ultrasound waves such that said ribbon is visible under ultrasonic visualization.    
   
   
       19 . The echogenic catheter of  claim 18 , wherein said catheter shaft is formed from urethane, nylon, polyethylene, PTFE or silicone, and said ribbon comprises a metal or a metal alloy.  
   
   
       20 . The echogenic catheter of  claim 19 , wherein said catheter shaft is formed from urethane or nylon, and said ribbon comprises stainless steel, a nickel-titanium alloy, a copper alloy or platinum.